1. Field of the Invention
This invention relates generally to a control system which receives a plurality of control commands and performs control operations in accordance with such commands, and more particularly is directed to a control system for a component-type television receiver or the like.
2. Description of the Prior Art
In recent years, there has been a tendency to provide television receivers comprised of separable components, such as, television tuners and monitors. Further, remote controllers for television receivers have also become popular because of the convenience they afford in effecting channel selection, volume control, mode selection and the like. The remote controllers usually employ a beam of infra red light as the transmission medium modulated by a control command. The modulated infra red light beam is received by a remote control command receiver or photosensor built into the television tuner and/or monitor.
One of the advantages of component-type television receivers is the possibility of physically separating the television tuner and television monitor when in use. However, such arrangement of the television tuner and monitor tends to make inconvenient the remote control of the television tuner and/or monitor. Conventional component-type television receivers have the remote control command receiver circuit or photosensor for receiving the infra red light beam from the remote controller built into the television tuner. In such case, if the television tuner is located remotely in respect to the television monitor, when effecting remote control, the user must aim the remote controller toward the television tuner, rather than toward the television monitor which is normally the focus of the user's attention. Therefore, when effecting remote control, the user must divert attention from the screen of the monitor and concentrate instead on accurately aiming the remote controller toward the television tuner.
In view of the foregoing, some recently provided component-type television receivers include remote control command receiver circuits with photosensors installed in both the television tuner and the television monitor, respectively. In such case, remote control can be effected by aiming the remote controller either at the television tuner or the television monitor which may be located relatively far apart. However, if the television tuner and monitor are situated close to each other so that the respective remote control command receiver circuits are simultaneously within range of the infra red light beam from the remote controller, both of the remote control command receiver circuits will respond simultaneously to a single remote control command. This can cause interference between the remote control command receiver circuits in the television tuner and monitor, respectively, and thereby cause difficulties in effecting remote control of the television receiver.
In order to avoid such difficulties due to possible interference between the remote control command receiver circuits in the television tuner and television monitor, respectively, some component-type television receivers have been provided with a control signal input terminal in the television monitor designed to be connected to a control signal output from a controller in the television tuner. In this arrangement, when the control signal input terminal of the television monitor is connected to the control signal output terminal of the television tuner, the remote control command receiver circuit in the television monitor is disabled. In other words, remote control of the television monitor through the remote control command receiver in the television monitor is possible only when the control signal input terminal of the monitor is disconnected from the control signal output terminal of the television tuner. However, such circuits used in the television tuner and the television monitor for the purpose of assigning command priority are relatively complicated and thus expensive. Furthermore, since the remote control command receiver circuit in the television monitor is disabled when the control signal input terminal of the monitor is connected to the control signal output terminal of the television tuner, direct remote control of the television monitor is seriously limited.